Ash　deposition　is　a　form　of　particulate　fouling,　and　appears　usually　in　boiler　economizers.　The　ash　deposition　increases　capital　expenditure,　energy　input　and　maintenance　costs.　An　analog　experiment　for　monitoring　ash　deposition　was　performed　from　the　analogous　objective　of　a　410　t/h　boiler　economizer　to　verify　the　rationality　and　reliability　of　the　ash-deposition-monitoring　model　presented　in　order　to　increase　the　security　and　economy　in　economizer　running.　The　analog　experiment　platform　is　a　tube-shell　exchanger　that　conforms　well　to　the　conditions　of　a　self-modeling　area.　The　analog　flue　gas　in　the　shell　side　is　the　heated　air　mixed　with　ash,　and　in　the　tube　side　the　fluid　is　water　heated　by　the　flue　gas.　The　fluid　state　in　the　water　side　and　the　flue　gas　side　follows　the　second　self-modeling　area.　A　4-factor-3　level　orthogonal　table　was　used　to　scheduled　operation　conditions　of　orthogonal　experiment,　with　the　4　factors　being　heat　power,　flue　gas　velocity,　ashes　grain　diameter　and　adding　ashes　quantity　while　the　three　levels　are　different　values　due　to　different　position　classes　in　every　factor.　The　ash　deposition　thermal　resistances　is　calculated　by　the　model　with　the　measure　parameters　of　temperature　and　pressure　drop.　It　shows　that　the　values　of　the　ash　deposition　thermal　resistances　gradually　increase　up　to　a　stable　state.　And　the　experimental　results　are　reliable　by　F　testing　method　at　α=0.001.　Therefore,　the　model　can　be　applied　in　online　monitoring　of　ash　deposition　in　a　boiler　economizers　in　power　plants　and　provides　scientific　decision　on　ash　deposition　prediction　and　sootblowing.